Answer:
236 in2
Step-by-step explanation:
To find how much cardboard is used, we need to find the surface area of the cylinder, minus the top surface.
The area of the base is:
A_base = pi*r^2
Where r is the radius of the base.
A_base = pi*(3.5)^2 = 38.4845 in2
The area of the side is calculated as:
A_side = 2*pi*r*h
Where h is the height of the cylinder.
A_side = 2*pi*3.5*9 = 197.9203 in2
So the total area we want is:
A_total = A_base + A_side = 38.4845 + 197.9203 = 236.4048 in2
Rounding to nearest square inch, we have A_total = 236 in2
